@property
    def input_keys(self) -> List[str]:
        """Return the singular input key.
        :meta private:
        """
        return [self.input_key]
    @property
    def output_keys(self) -> List[str]:
        """Return the singular output key.
        :meta private:
        """
        if not self.return_intermediate_steps:
            return [self.output_key]
        else:
            return [self.output_key, "intermediate_steps"]
    def _call(self, inputs: Dict[str, Any]) -> Dict[str, Any]:
        llm_chain = LLMChain(llm=self.llm, prompt=self.prompt)
        input_text = f"{inputs[self.input_key]} \nSQLQuery:"
        self.callback_manager.on_text(input_text, verbose=self.verbose)
        # If not present, then defaults to None which is all tables.
        table_names_to_use = inputs.get("table_names_to_use")
        table_info = self.database.get_table_info(table_names=table_names_to_use)
        llm_inputs = {
            "input": input_text,
            "top_k": self.top_k,
            "dialect": self.database.dialect,
            "table_info": table_info,
            "stop": ["\nSQLResult:"],
        }
        intermediate_steps = []
        sql_cmd = llm_chain.predict(**llm_inputs)
        intermediate_steps.append(sql_cmd)
        self.callback_manager.on_text(sql_cmd, color="green", verbose=self.verbose)
        result = self.database.run(sql_cmd)
        intermediate_steps.append(result)
        self.callback_manager.on_text("\nSQLResult: ", verbose=self.verbose)
        self.callback_manager.on_text(result, color="yellow", verbose=self.verbose)